Coughs can be classified under two headings: dry and productive. Dry coughs don't produce sputum while productive coughs do. A chronic dry cough (when coughing has lasted longer than eight weeks) is typically caused by smoking. Resulting from inflammation of the lungs, smokers' coughs are loud and hacking, typically tickling the throat on their way out. Often, respiratory infections begin with dry cough then, over time, the cough becomes productive.
The Common Cold
Easily spread, this viral infection affects your upper respiratory tract, which includes your nose and throat. It enters through your nose, collecting there and also travelling to your throat. The throat spasms as it tries to get rid of the intruding virus, resulting in a persistent cough. As you undoubtedly know from your numerous cold experiences, while the congestion, sore throat and sneezing seem bad at the moment, most colds disappear without any lasting effects. However, a viral infection such as this can be followed by more serious conditions.
Bronchitis is a condition characterised by inflamed bronchi (air passages to the lungs). Acute bronchitis (usually present less than three weeks) comes immediately after a viral infection, like a cold or the flu. It begins in the upper respiratory tract but spreads down into the lungs. Generally, the cough associated with bronchitis begins dry and then becomes productive at its most severe stage. As the worst of it passes, coughs become dry again. While other acute bronchitis symptoms (including wheezing, hoarseness and a slight fever) generally only last for about a week, this hacking cough could remain for months. The cough associated with chronic bronchitis is generally accompanied by mucus and lasts much longer.
Laryngitis is when your voice box (larynx) becomes inflamed. It may occur due to irritation or infection. Because your vocal chords are located inside the larynx and can therefore no longer move smoothly and create the appropriate vibrations, a hoarse, weak or lost voice is the most evident symptom of laryngitis. A very dry cough usually accompanies laryngitis, which typically follows viral respiratory infections (like a cold and flu) or results from vocal strain.
An infection of the upper respiratory tract, whooping cough is caused by airborne bacteria. The bacteria produce toxins that inhibit the respiratory tract's removal of germs. As a result, mucus builds up in the airways and causes persistent coughing. Additionally, the bacteria cause the bronchi to become inflamed and narrow. Whooping cough is particularly contagious at the onset, when it seems like a cold with mild coughing, sneezing and a runny nose, but remains somewhat contagious throughout. When the infection is at its worst, loud, hacking coughs are uncontrollable and so violent that they result in exhaustion. Following this, the patient may begin to gain strength but a loud cough persists until the infection is completely gone.
Asthma sufferers have extra sensitive, easily irritated air passages. Irritants cause your airways to become inflamed, inciting your muscles to tighten and too much mucus to be produced. These narrowed passages mean it's difficult to get enough air into the lungs. Wheezing is the most common effect of this but, in a version called "cough-variant asthma", a dry cough is usually the only symptom. This fact makes it quite difficult to diagnose. While it's safe to say this condition is uncommon, exactly how common isn't known. A Canadian College of Medicine case report revealed that "studies have not compared the prevalence of cough variant asthma to the symptoms and signs typically associated with classic asthma, namely wheezing, dyspnea, cough and variable airflow obstruction."
Some more possible causes of a dry, hacking cough include allergies, asbestosis, lung cancer and ACE inhibitors.